Electrochemical reduction of chromate ions from dilute artificial solutions in a GBC-reactor

Reduction of chromate in very low concentration (20 ppm) has been carried o ut in a GBC reactor. Final concentrations below 0.5 ppm have been achieved at reasonable reaction rates. Spontaneous reduction of chromate by hydrogen in a GBC reactor without an external power source requires careful selecti on of cathode material. Chemically stable materials such as titanium and RV C tend to passivate when in contact with chromate solution and are unsuitab le for use as cathode materials. Graphite, active carbon and graphite felt show no obvious passivation. Reduction of oxidized groups and oxygen are th e major side reactions. These occur significantly, especially when using an activated carbon bed as a cathode.